1. Field of the Invention
The present invention relates to a document processing apparatus having a communication function.
2. Related Background Art
Conventionally, for example, a document processing apparatus with a facsimile function, which can create and edit a document using character code data, and can perform a facsimile sending operation by converting the character code data into image data, is provided.
A document processing apparatus of this type sends document data stored in an external memory device such as a floppy disk, a hard disk, or the like, or document data stored in an internal memory such as a RAM. More specifically, in the document processing apparatus, in terms of the data processing time, the communication speed, and the like upon execution of a sending operation, after a document to be sent is converted from code data into image data in advance, the image data is compressed by a method regulated by, e.g., the G3 mode of the CCITT, and the compressed data is temporarily stored in, e.g., a floppy disk. Thereafter, the sending operation is started.
In a document processing apparatus of this type, data which is sent already is deleted after a sending operation, and only document data which is not sent yet is left, so that the maximum amount reception data can be stored.
However, when sent data is not saved, if an operator wants to partially modify the sent data to create a new document, since the original document is not saved, he or she must create a document from the beginning.
Similarly, when a document already saved in a floppy disk is read out, and is sent after it is partially modified, if the modified document is not saved, the original document must be modified again when necessary.
On the other hand, when sending data is stored in a floppy disk without limitations, a large-capacity device is required, resulting in an increase in cost.
Therefore, in order to properly manage sent documents, an operator must decide whether or not a document should be saved every time he or she sends the document.
In a document processing apparatus of this type, when a document is created and sent, a mode for attaching a cover page is normally designated before a sending operation. In this case, a predetermined form of a cover page corresponding to a type of each apparatus is prepared and sent with the document. If a desired form is not prepared, destination data is input in a document text, and the document text including the cover page is sent.
However, the above-mentioned apparatus suffers from the following drawbacks:
(1) Even when a memo is sent, the cover page must be attached. When the memo is sent to a plurality of destinations, the cover page is also sent to these destinations. PA1 (2) When a document having the same content is sent to a plurality of destinations like in a multi-address communication mode, if no cover page is attached, a plurality of destination data must be input in a document.
Conventionally, a special-purpose facsimile apparatus is known, and has a special-purpose data storage area for performing a facsimile sending/reception operation. Recently, electronic apparatuses such as personal computers, wordprocessors, and the like having a facsimile function are commercially available. These apparatuses generally have both external and internal memory devices, and are designed to have a considerably large memory capacity. In addition, these apparatuses use a CPU, which can perform high-speed processing. However, some apparatuses cannot assure a memory capacity, and do not perform a facsimile function service during creation of a document.
In the above-mentioned prior art, an electronic apparatus, which can always support a facsimile function, requires a large memory capacity, and also requires a CPU, which can perform high-speed processing, and has high-grade functions, resulting in an increase in cost.
Therefore, when a facsimile function is added to a compact electronic apparatus, a facsimile reception operation cannot be performed during processing of a document, and can be performed in only a waiting state. In addition, a reception mode must be requested in advance through a telephone communication.
When an electronic apparatus having a facsimile function is of a separation type, that is, the facsimile function is added by an optional unit, the optional unit is connected to a bus expansion port in the same manner as a versatile RS232C serial interface of a document processing apparatus, or an expansion I/O board of a personal computer, or to a printer port. When the electronic apparatus is of a built-in type, a special-purpose microprocessor for a facsimile function is arranged, and document processing and facsimile control are independently performed by special-purpose microprocessors. Each microcomputer system is provided with peripheral circuits, a ROM for storing programs, various tables, a data processing RAM, and the like.
However, in the above-mentioned prior art, from the viewpoints of facsimile image processing (dot density processing), the facsimile function is normally executed in a dot density of about 200 dpi (8 pel/mm in the horizontal direction; 3.85 dots/mm in the vertical direction) in the G3 mode of the CCITT standards, while the document processing microcomputer system normally has character generation (CG) ROM data such as fonts corresponding to 200 dpi for data transmission. There are cases wherein the dot density of the ROM data coincides with that of a printer or a display, and a case wherein they do not coincide. For example, when a high-resolution printer is used, the microcomputer system has many font data such as printer CG font data, display CG font data, and the like.
From the viewpoints of data strings, facsimile data are data strings in the horizontal direction, while those of a wire-dot or thermal printer are data strings in the vertical direction. Therefore, in the prior art, conversion of data strings is required. Furthermore, as for the dot density, when an apparatus cannot have many CGs, dot density conversion for forming font data having a facsimile dot density from a single CG is also required. The document processing microcomputer system and the facsimile microcomputer system share these processing operations. In general, since the facsimile microcomputer system mainly performs communication control such as facsimile data compression, modem processing, and the like, the document processing microprocessor system performs other processing operations such as dot density conversion, data string conversion, and the like. For this reason, an extra memory is arranged independently of the systems, or a very long program processing time is required for the above-mentioned processing.
Even in the separation type apparatus to which the facsimile function can be added, the above-mentioned loads are imposed on the document processing system side.
In an apparatus such as a facsimile apparatus, an image reader, or the like, for photoelectrically reading an original image, converting the read image data into digital dot image data, and outputting the converted data, image data read at a resolution (dot density) of, e.g., 200 dpi (dots/inch) is printed by a printer having the same resolution of 200 dpi. When 200-dpi image data is printed using a 400-dpi printer, the 200-dpi image data is easily converted into image data having a dot density of 400 dpi by software processing, and the converted data is printed. However, when resolution conversion is not relatively easy, for example, when image data having a dot density of 180 dpi is printed by a 200-dpi printer, complex calculations are required for causing the dot density of the image data to coincide with that of the printer. For this reason, the 180-dpi image data is directly printed by the 200-dpi printer without changing the dot density.
However, when image data is printed by a printer having a resolution different from the dot density of image data without performing dot-density conversion, a printed image size becomes different from an actual image size. In order to remove such a drawback, an output apparatus such as a printer having the same resolution as that of read image data must be equipped. However, it is not practical to equip all the printers having the same resolutions as those of image data. Therefore, processing for converting the dot density of image data is necessary. When dots are added or deleted by, e.g., software processing to perform dot-density conversion, the overall processing speed is undesirably decreased.